T Protein Serotyping and Antibiotic Sensitivity Test for Streptococcus pyogenes Obtained from Patients with Pharyngotonsillitis and Healthy School Children

Cha, Sungho; Cho, Byongsoo; Suh, Jintae; Hwang, Kyujam; Bae, Songmee; Lee, Younghee

Abstract

BACKGROUND: In the mid-1970s and late 1980s, outbreaks of erythromycin-resistant streptococci in Japan and Finland were likely to be associated with the increased consumption of macrolides. Because of the lack of routine antibiotic sensitivity for Streptococcus pyogenes, the reported percentage of resistant strains was only 2% in 1994 in Korea. We tried to determine the rate of resistant strains considering the high occurrence of penicillin-resistant pneumococci and antibiotic purchase without prescription in our country.
METHODS
Twenty-four strains of S. pyogenes were isolated from children with pharyngotonsillitis in Kyunghee University Hospital, Seoul, Korea from Feb. through Aug. 1998. Forty-four strains obtained from healthy school children living in Uljin, Kyongsang-bukdo and Hongreung, Seoul in 1998. All isolates were serotyped by T-agglutination (Sevapharma, Czech Rep) and minimal inhibitory concentrations were determined for penicillin, erythromycin, vancomycin, tetracycline, cefotaxime, and clindamycin by agar dilution method according to National Committee for Clinical Laboratory Standards.
RESULTS
The carrier rates in Hongreung and Uljin were 4.1% and 13.3%, respectively. Twenty-two out of 24 (91.6%) strains from pharyngitis and 32 out of 44 (72.7%) strains from normal children were typed by T agglutination test. The most common T types were T12 (54.2%) and T4 (33.3%) in pharyngitis, whereas the most common T types were T12 (45.5%), non typable (27.3%), and T4 (15.9%) in healthy carriers. All of the strains from pharyngitis were susceptible to penicillin, vancomycin, and cefotaxime. However, 13 out of 24 (54.2%) strains were resistant to erythromycin, and 11 isolates (45.8%) were resistant to clindamycin and tetracycline. Ten out of 13 isolates of T12 and one isolate of T28 were multi-resistant to erythromycin, clindamycin, and tetracycline. Two isolates of T4 were resistant to erythromycin.
CONCLUSION
Almost half of isolates obtained from a university hospital in Seoul are multidrug-resistant Streptococcus pyogenes. Serial monitoring of antibiotic susceptibility test and a nationwide survey accompanied by molecular epidemiologic studies are needed to determine the occurrence and spread of resistant strains from different geographic areas.